1. Field of the Invention
The present invention relates in general to a scoring and breaking machine. In particular, the present invention relates to a tile scoring machine which maintains constant pressure upon the cutter wheel throughout the scoring operation and that achieves a sharp break even on soft tile.
2. Description of the Related Art
The general purpose of a scoring and breaking device is to provide a tool by which a user may break a material, such as tile, glass, plastic, ceramic, etc., along a desired line. By breaking the material, the user avoids the difficult task of cutting an often extremely hard material. The break is guided along a desired line by first scoring or cutting a slight groove in the material along this line.
Conventional scoring and breaking devices have been provided for cutting tile that comprise a base for holding a tile and one or more guide rods aligned parallel thereto. The guide rods slidably support a tile cutter and guide the cutter across the tile. The tile cutter is connected to a handle that the operator uses to force the cutter across the tile.
One type of conventional tile cutter (e.g., U.S. Pat. No. 4,026,262) utilizes the handle as a lever arm, by which the operator applying a scoring pressure to the cutter. The operator varies the scoring pressure on the cutter by varying the torque on the handle. However, this arrangement is disadvantageous since operators inadvertently vary the scoring pressure. Typically, the user grows fatigued after several scoring operations since the user must apply a large scoring force during each operation. Also, users develop muscle cramps as the scoring motion is awkward. Consequently, the depth of the score is uneven or otherwise improper, causing an uneven break.
Further, the system of the '262 patent is exclusively a tile cutter and thus requires a separate mechanism to break the tile. In this conventional system, to score a tile the user must pull the scoring tool across the tile. This pulling action is disadvantageous since it requires a stronger grip and quickly fatigues the user's forearm. Instead, it is preferential for the user to push the scoring tool across the tile. By pushing the tool, the user is able to push against the handle of the tool with the palm of the user's hand, thereby requiring less wrist strength. This motion requires less energy.
An alternative system (e.g., British Patent No. 932,640) combines the cutting and breaking operations within a single apparatus. However, this system employs compound lever arms to perform cutting and breaking. Specifically, it connects a tile cutter and a tile breaking member to the operator's handle via separate rods. As the handle moves through a first portion of a stroke, a first linking rod drives the cutter across the tile to effect a score. As the handle moves through a second portion of the stroke, a second linking rod forces the breaking member downward against the tile to effect a break.
The cutter in this alternative conventional system includes a spring to maintain pressure on the scoring wheel at all times. The scoring wheel and spring are slidably housed within a hollow screw threaded into the cutter housing. The scoring wheel is attached to a small threaded rod extending through the spring and beyond the top of the hollow screw. A nut on this threaded rod is used to adjust the tension of the spring, while the hollow screw is used to adjust the depth of the score.
However, the continuous pressure of the spring directly on the scoring wheel necessitated a complex mechanism for adjusting the scoring depth for tiles having different thicknesses. Also, when it is desirable to move the cutter across the tile without scoring, the screw must first be substantially unscrewed.
Another conventional system (U.S. Pat. No. 3,889,862) has been proposed which performs the cutting and breaking operations. This system includes multiple springs, each of which exerts a different amount of force upon a scoring wheel in order to provide different scoring pressures for various kinds of materials to be cut. The stiffest spring is manually engaged and disengaged with a bayonet lever to permit this stiffest spring to function only when cutting plastic. Another lever is provided to raise the scoring wheel to an inactive position when moving the scoring head between scores. A third lever is provided to push the cutting wheel across the tile, while a fourth lever is provided to force the breaker bar against the tile. However, this system is unduly complex as it requires the use of multiple levers and multiple springs.
Further, with regard to the breaking operation, conventional systems have provided various base plates that support the tile during breaking. One conventional system (British Patent No. 932,640) utilizes, as a base, an inverted V-shaped anvil aligned below and parallel to the path of the scoring wheel. The scoring mark on the tile is aligned parallel to, and directly above, the apex of the anvil to effect a break. Another system (U.S. Pat. No. 3,889,862) utilizes an anvil having two slightly inclined sides which define an apex that designates the line of the score or cut. In this second system, the anvil includes, along its apex, a slight notch or depression to avoid contact with the cutting wheel. However, these conventional systems do not provide a sufficiently clean break as the tile will chip off along either side of the break or the break will not precisely follow the scoring path.
Accordingly, the need remains for a tile scoring and breaking tool having improved features and operating techniques to address the problems and drawbacks heretofore experienced with earlier devices. The primary objective of this invention is to meet this need.